The present disclosure relates to the field of infusion devices, and more particularly to peripheral intravenous (IV) catheters.
A catheter assembly for an IV catheter generally includes a flexible catheter, or catheter tube, coupled to a distal end of a catheter adapter, which can include a catheter hub. The catheter adapter retains the catheter tube so that other components can interact with the catheter tube. In order to place the catheter tube in the patient's blood vessel, an introducer needle is coupled to the catheter adapter so that the needle extends through the catheter adapter and catheter tube, with the sharp distal tip of the needle positioned just beyond the distal end of the catheter tube. The clinician uses the introducer needle to penetrate the patient's tissue and place the distal end of the catheter tube in a blood vessel.
Once the needle tip and the catheter tube are in the vessel, the clinician typically uses blood flashback to confirm that placement is correct. For example, when the needle tip and/or the catheter tube is properly placed in the vasculature of the patient, blood from the vessel may flow through the needle and/or the catheter tube into the catheter adapter. When the clinician sees the blood in the catheter adapter, the clinician knows that the distal tip of the needle and/or the distal end of the catheter tube is in place in the blood vessel.
It is generally desired that blood flashback flow be contained within the catheter adapter. Often, an elastomeric septum in the catheter adapter creates a seal to contain the blood in a distal chamber of the catheter adapter. However, in some instances the seal may lead to excessive positive air pressure in the catheter adapter or head pressure in an enclosed space, which positive air pressure may hinder or prevent blood flow into the catheter adapter. Thus, even though the catheter tube may be correctly placed, blood flashback may be less prominent, delayed, or prevented altogether. To relieve such positive air pressure, some prior catheter assemblies employ air vents that can direct air from the distal chamber past the sealed septum. However, air vents are vulnerable to leaking blood.
Once it is verified that the catheter tube is correctly placed in the blood vessel, the introducer needle is removed, and a source of IV fluids can be attached to the catheter adapter via a coupler such as a luer or threaded coupler. It is desirable to have a structure in which blood that may accumulate in the catheter adapter can be effectively flushed out of the catheter adapter by IV fluids once such fluids are attached.